Crank case closure and holding means



March 1, 1932. c. B. JAHNKE CRANK CASE CLOSURE AND HOLDING MEANS Filed April 14, 1927 Patented Mar. 1, 1932 UNITED STATES. PATENT OFFICE oI AnLEs 3.. JAHNKE, or BELOII, wIscoNsIN; Ass enoR 'Io FAIRBANKS, MORSE a COMPANY, or CHICAGO, ILLINOIS, a CORPORATION or ILLINOIS CRANK CASE CLOSURE Application filed April 14,

Thisinvention relates to improvements in internal combustion engines and more particularly to an improved crank case closure member and holding means therefor, applicable to engines using crank case compression.

An object of this invention is the production of a closure member, with its accompany ing retaining and positioning means, forrendering air tight certain necessary openings in engine crank cases.

A further object is to obtain a closure means of the class described which may be fitted to an opening to be sealed, without the useof screws and without the necessity for accu Z5 ratel'y machining any of the parts involved.

A further object is the creation of a device of the class described which may be installed without the use of expensive skilled labor;

A further object is the creation of an eflias cient, dependable closure means for a crank case opening, which consists of minimum number of parts and which can be manufactured and installed at less expense than prevailing designs.

Further ob'ects and. advantages of this invention will appear from the drawings and the following description thereof.

Although myinvention consists'largely in the construction and arrangement of parts hereinafter described and particularly pointed out in the claims, yet I do not limit my invention to the precise form or construction of parts shown or the several parts thereof, inasmuch as various alterations maybe made without changing the scope of my invention.- In the drawings, Fig. 1 is a fragmentary elevation, partly in section, showing portions of the crank shaft, crank case andupper base 'of an engine to which my invention is applied 120 and showing a sectional view of an approved form of my air stop plate assembly; Fig. 2 is a side elevation of an improved form of air stop plate and securing means; Fig. 3 is a sectional elevation of a. modified form of air 10* stop plate assembly in which two or more plates are used and in which the fastening means consists of one or more through bolts, as shown.

Referring by numerals to the drawings, 5

: 0. indicates a crankshaft of usualform revolv- AND HOLDI G MEANS 927. Serial No. 183,701.

ing in a crank case 6. The upper portion of the crank case or upper base is indicated at 7 cates an oil duct, supplied from a suitable source for lubricating the bearing. An opening 15 is normally provided above the bearing in order to permit the removal of the bearing cap 8 and the shell 9 for access to the bearing. After the bearin is assembled this opening 15 must be provided, with, a closure member for the retentionof oil inside the crank case and for the retention of crank case compression; in engines of this type. As a closure member for this purpose I prefer to use an air stop plate 11. This plate consists of a piece of metal approximately semi-circular in form and substantially of the shape indicated in Fig. 2. The plate 11 is held in place by means of a clamp 13 sometimes known as a C clamp. The upper portion of each of the C clamps engages the upper base in themannershown. Bolt or bolts 12 preferably extend through the plate 11 and through the C clamp 13 to position the plate. next to the inside surface of the upper base 7.

Bolts 12' are preferably carriage bolts of the ordinary type, the square shank of this type of bolt serving to position the bolt inthejstop plate and prevent turning during assembly. If desired, a suitable gasket 14 may be interposed IISXttO'tllGStOP plate 11 for the purpose of making anabsolute air tight .jointo at, this point. Gasket'l' may be 0t any suitable type; In lieu ofgasket 14 or. even when a gasket is employed, it is sometimes advisable to grind to smoothness a face 16 next to the stop plate.- For the purpose of positioning the stop plate 11, I may provide one or more dowels 17 which are by preference located in the bearing cap 8, or may be, if preferred, located in the air stop plat-e; Thedowels '17 are designed to fit into corresponding recesses 18; Usually, two such dowels and recesses are sufficient to position'the, plate. The use tau with entirely by notching or recessing bearing cap 8 in such a manner that it is impossible to locate the air stop plate 11 in any except the correct position.

Fig. 3 shows a modified form of stop plate assemblyin which I use two or more similar air stop plates and position the plates by the use of one or more through bolts 12. This arrangement has the advantage of providing a double, air tight joint in place ofthe single joint afiorded by the use of a single plate. This modification dispenses with the use of the C clamp 13, referred to above. The latter construction illustrated in Figsl andQ is a preferred form due to lower manufacturing and assembly costs and entirely satisfactory operation. i

The described forms of air stop plate assembly were devised especially for use between adjacent crank chambers of engines employing crank case compression. The novelty of the arrangements described lies chiefly in the manner of assemblingand'positioning the plates. The older prevailing practice is to clamp a single plate against the face of the upper bearing cap and against the wall of the upper base or of the crank case. Tosecure the plate the prevailing practice is to use a-series of screws, engaging tapped openings 011 the inside of the crank case wall. The tapping of suitable holes for such screws on the inside of the crank case involves much expense and difficulty in machining them, because their location is accessible only to portable machines. Skilled labor must necessarily be employed for this purpose, with the consequent expense. It will be seen that by this invention I have eliminated the necessity for machining the screw holes referred to above, and as a result have greatly reduced the cost of the air stop plate assembly. Although this problem has been encountered particularly in two cycle, crank case compression engines, the same arrangement of partsmay just as well'be usedin either two or four cycle engines which may or may not employ crank case compression. Vhile originally designed for use in multicylinderengines, the device may as well be of value as an end closure for the crank case of a single cylinderengine, or in other containers for fluid under pressure.

What I claim is g V V V 1. In an engine having a crank case adapted for compression, a bearing in said crank case, a bearingcap having a plane surface, said crank case having a wall opening adapted to permit removal of portions of said bearing, and a substantially semi-circularv plate for closing said opening, positioned adjacent the plane surface on said cap, a bolt, said plate being held in position by said bolt extending through the plate and opening, anda clamping member of substantially 1C shape adapted centrally to receive and to coact' with said bolt and having its ends disposed respectively in engagement with the outside surfaces of the plate and the crank case wall.

In an engine, a crank case adapted to contain scavenging air, a bearing carried by a wall of said crank case, a bearing cap having a. plane surface, a'wall opening in the crank case for assembly and disassembly of the bearing, a stop plate of partly circular form, serving as a cover for said wall opening, said plate having a partly circular recess conforming substantially to a portion of the bear-111g and being positioned against the plane surface on said cap, and against the 1nside wall of the crank case, and holding means so for the plate, said means including a bolt having a'portion of angulate section extending through a corresponding portion of the plate and through said wall opening, and a clamping member of curved longitudinal section, held by said bolt-and plate, with one terminal edge portion in gripping engagement with a portion of the crank case wall, and its opposite edge portion in abutting engagement with the plate.

3. In an engine employing crank case compression. a crank case, a main engine-bearing carried by a wallof the crank case, a cap for the bearing, the crank case having a wall opening "about a portion of the bearing, arranged for access to, and assembly and disassembly of the bearing, a plate within the crank case and adapted as a closure for said opening, finished interior surfaces on the cap and crank case wall for receiving the 1 0 plate and adapted to form therewith an air tight joint, means for positioning the plate, said means including a plurality of curved clamping members, each having its opposite terminal edges engaging, respectively, the outside crank case wall and the exterior surface of the plate, a bolt for each of said clamping members, extending through said access opening, plate and the associated clamping. member and adapted to secure said plate and member adjacent opposite surfaces of a crank case wall portion, and means constituted by each of the bolts and bolt-receiving portions of the plate, for preventing axial movement of the bolts during assembly.

. CHAR-LES B. JAHNKE. 

